Based on anecdotal clinical observation and a limited number of objective studies, genital tract infection with human papillomavirus (HPV) appears to be activated in pregnancy. This project will determine the frequency with which cervical HPV infection can be detected in a large cohort of pregnant women. Cervical cells will be assayed for the presence of HPV types 6, 11, 16, 18, 31, 33, and 35 by Southern blot. These women will be followed throughout their pregnancy and into the postpartum period to evaluate changes in the amount of HPV DNA present. These results will be compared to those obtained from two cohorts of non-pregnant women, one seen for routine care in a gynecology clinic and a second seen in an STD clinic. Adjustments will be made for sexual activity and other important parameters in the analysis. More sensitive assays for HPV sequences will be developed using the polymerase chain reaction (PCR) DNA amplification method to provide a more accurate estimate of the incidence of HPV infection in the populations studied and to determine if low-grade (or latent) HPV infections which could be activated would explain any differences between the two patient populations. To evaluate the mechanism of HPV activation in pregnancy, the PCR method will also be used to assay for the presence and amount of mRNA from the E6-E7, E2, E4, and L1 regions of the HPV genome found at different times in pregnant and non-pregnant patients who are infected with HPV 16 (and possibly other types). The specimens subjected to RNA analysis will also be assayed for the presence and quantity of the E4 and L1 proteins. Completion of these studies will provide better information on the importance of HPV as a pathogen in the pregnant woman and will provide a clearer picture of the control of HPV replication in the cervix.